1. Field of the Invention
The invention relates to a panel, in particular a floor panel, with a core that consists of a wood material or a wood material-plastic mixture, a top side and a bottom side, which panel has on a first lateral edge a lower locking element, which comprises a first arm that is arranged on the bottom side of the panel and that extends from the first lateral edge, and a first hook element with an undercut that is arranged on an outer end of the first arm, and which panel has on a second lateral edge that is opposite to the first lateral edge an upper locking element with a second arm that is arranged on the top side of the panel and that extends from the second lateral edge, and a second hook element, which has at least one locking nose, arranged on an outer end of the second arm, such that two identically designed panels can be connected and locked to one another in the horizontal direction and in the vertical direction after the locking nose of one panel is snapped into the undercut of a second panel.
2. Discussion of Background Information
Such a panel is known, for example, from DE 199 29 896 A1. Two of the panels described there are connected to one another by a joining motion that runs perpendicular to the placement plane. In this case, both the lower locking element and the upper locking element are widened continuously in an elastic manner until the locking nose of one panel snaps into the undercut of the second panel. Two thus connected panels are connected and locked to one another both in the horizontal direction and in the vertical direction.
The strength of the lock, i.e., the force that has to be applied to separate once again two panels that are connected and locked to one another, is in this case, i.a., determined in how far the locking nose of one panel can snap into the undercut of the second panel. The further the locking nose engages in the undercut, the stronger the lock in the panels is. To achieve as strong a locking as possible, the locking elements are to be widened as far as possible in an elastic manner. To this end, the material, of which the two locking elements consist, has to have a relatively high elasticity.
DE 103 05 695 A1 also discloses floor panels that can be connected to one another by a joining motion that runs perpendicular to the placement plane. The panels have an essentially mushroom-shaped locking strip on a lateral edge and an essentially mushroom-shaped locking groove in cross-section on a lateral edge opposite to this lateral edge. When two panels are joined together, the essentially mushroom-shaped locking strip is now inserted into the locking groove. In this case, the locking groove has to be widened elastically by the mushroom shape until the mushroom-shaped locking strip snaps in.
Also, in this case, the locking groove has to be widened as far as possible in an elastic manner as far as possible to achieve a strong locking of the two panels relative to one another.
Also, DE 202 03 311 U1 discloses floor panels that can be locked to one another by a vertical joining motion. Also, in the solution shown there, a locking nose of one panel snaps into an undercut of the other panel. Also, in this case, the locking element of one panel has to be widened to ensure locking.
As core material for the panels, in particular medium-density fiber plates (MDF) or high-density fiber plates (HDF) are suitable. The latter have great strength, so that they can readily withstand the stresses to which floor panels in particular are exposed from walking. It is disadvantageous that these vehicles are elastically deformable only to a slight extent. As a result, the locking elements can be widened elastically only within a limited extent. Thus, the possible strength of the locking of two panels is also limited by the selection of the core material.
DE 10 2007 015 048 A1 discloses panels in which a spring element, which can snap into a groove provided for this purpose on the opposite side of another panel, is formed on at least one lateral edge. The spring element extends along the lateral edge and is connected to the core of the panel only at its two ends. In between, it is released by two grinding processes and can accordingly be deflected horizontally. When the two panels are connected, the spring element is deflected and snaps into the groove that is provided for this purpose in the second panel when the two panels have reached the previously defined end position. As a result, both panels are connected and locked to one another at least in the vertical direction.
The strength of the locking is determined in this case by the thickness of the spring element. In particular in the case of thin panels, the spring element must also be designed very thin, so that in particular in these cases, it can result in a locking that is not designed to be strong enough.
DE 10 2007 020 271 A1 discloses floor panels, on whose lateral edges locking elements for vertical locking are provided. In this case, a locking projection of a panel emerges through a window on the other panel and engages the peripheral wall of this window. By the design of this window, a bending beam clamped on two sides is formed, and said beam is deflected for locking and snapped back again into the locking position.
It is disadvantageous that this bending beam, which extends along a lateral edge of a panel, is connected to the panel only at its two ends. In this respect, in particular in floor panels that are laid on an uneven base, the heavy loads that arise from walking can cause the connection between the bending beam and the panel core to break. In this case, the two panels are no longer locked to one another.
Moreover, because the locking element penetrates the window, it can happen that the bending beam can have only about one-third of the panel thickness count as thickness. In particular in the case of thin panels, the stability of the locking is thus greatly reduced such that this solution can be applied only for thick panels.